1. Field
Communication systems in which a fixed size information block is transmitted to one or multiple receivers, such as the long term evolution (LTE) of the 3rd Generation Partnership Projection (3GPP), may benefit from a structure, in which a downlink control information (DCI) format, or more generally the fixed sized information block, can be extended by a small number of bits and still be backwards compatible with older terminals, which do not need the extra bits or may not even be aware of this extension.
2. Description of the Related Art
In the long term evolution (LTE) of the 3rd Generation Partnership Projection (3GPP) there are several downlink control information (DCI) formats available optimized for different transmission schemes. A new major feature in the system often requires a new DCI format even though only often a single (new) additional bit will be needed, as such. The standardization effort for a new DCI format is big, requiring extensive discussions in several meetings as well as considerations on the number of blind decodings needed, and is therefore typically not standardized unless deemed absolutely necessary. Moreover, different new DCI formats as such might be needed for different features and/or combination of features, increasing the total amount of possible DCI formats to specify, implement, and test for.
Relatively minor new features in wireless telecommunication systems are often handled with existing downlink control information (DCI) formats by reinterpreting bits, or by making some implicit assumptions regarding some other behaviors. The reuse of DCI formats for new features is limited, because the number of bits in DCI format is limited.
Conventionally, in systems like LTE, there is no structure, in which the DCI format, or more generally the fixed sized information block, can be extended by a small number of bits and still be backwards compatible with older terminals, which do not need the extra bits or may not even be aware of this extension.